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Exotic neutron-rich nuclei play an important role in r -process nucleosynthesis. We study the effect of including proper nuclear structure to calculate neutron capture and photodisintegration rates, especially for 19C and 20N, under the aegis of post-form distorted wave Born approximation (FRDWBA). Considering a network of neutron-rich C–N–O isotopes, we show the effect on abundance calculations in a neutrino-driven wind environment of a core-collapse supernova at two critical temperatures T 9 = 3.4 and 0.62. The results are compared for nuclear physics inputs sourced from the FRDWBA, statistical estimates, and standard databases. At temperatures T 9 = 3.4, where alpha capture, or at T 9 = 0.62, where the neutron capture dominates, one can distinguish the effect of accounting for the exotic nature of the nuclei involved. Furthermore, we assess the impact of varying neutron capture and photodisintegration rates involving halo or bubble structures on the abundances within the network. [ABSTRACT FROM AUTHOR]

The weakly bound nucleus 29F locates near the neutron drip line. Experiments have confirmed that it is the heaviest two-neutron halo nucleus discovered up to now. To understand the halo structure in 29F, we explore the weakly bound and resonant levels close to the Fermi surface with the complex momentum representation method. Not only the narrow resonances and the broad resonances. Since the broad resonance 2 p 3/2 is disclosed, the p âˆ' f inversion and N = 20 shell gap quenching are found. The last valence neutron can occupy the weakly bound level 1/2[310], composed mainly of p 3/2â€"component, or the 1/2[211], composed mainly of s 1/2â€"component. Since the wavefunctions of p and s â€"components extend to a large range in the coordinate space, which results in the density distributions of the levels 1/2[310] and 1/2[211] being considerably diffuse. This is the most likely cause of halo formation in 29F and the halo may be formed by the p â€"component, s â€"component, or their mixtures by pairing correlations. [ABSTRACT FROM AUTHOR]

A large wealth of data and a variety of models led to significant progress in understanding the spectra of deformed nuclei. However, a robust theoretical approach, which is less reliant on adjustable parameters is still elusive. Due to the scarcity of data, this drawback gets more pronounced while studying the exotic nuclei. With the motive to overcome this difficulty, we have developed the nonadiabatic quasiparticle approach for the description of rotational states in triaxial deformed odd–odd nuclei. The rotation-particle coupling is carried out utilizing an appropriate basis transformation such that the matrix elements of the odd–odd system can be written in terms of the rotor energies. This provides the advantage of studying the role of core more efficiently as compared to the conventional particle rotor model. The residual interaction between the valence proton and neutron is incorporated in two reliable ways, namely, the constant potential form and the zero-range interaction. [ABSTRACT FROM AUTHOR]

The exotic nuclei are a fertile source of new features of nuclear structure. The evolution of new shell gaps accompanied by quenching of classical magic numbers is one of the marked features in these nuclei. These studies aimed to search and explore such behavior and find major significance on both the experimental and theoretical fronts. Here, we present an inclusive study and significant evidence of the existence of deformed shell closure at the neutron number N = 100 in rare earth Nd, Sm, Gd and Dy nuclei, obtained from the persistence of a peak in the analysis of symmetry energy and its bulk and surface components, over the isotopic chains of these nuclei, within the coherent density fluctuation model (CDFM). The relativistic mean field densities, employing the NL3 and recently developed IOPB-I parameter sets, have been used as an input within CDFM. This result is in excellent agreement with our earlier prediction of deformed magic shell closure at N = 100 in rare earth nuclei [Satpathy et al (2004 J. Phys. G 30 771); Ghouri et al (2012 Phys. Rev. C 85 064327)] and further reinforced by the experimental confirmation of deformed magicity at N = 100 in 162Sm and 164Gd nuclei [Patel et al (2014 Phys. Rev. Lett. 113 262502)]. An important consequence of the work is that N = 100 isotopes of these nuclei can serve as a waiting point in r-process nucleosynthesis and influence the heavy nuclei formation in astrophysical entities. [ABSTRACT FROM AUTHOR]

The study of exotic nuclei is one of the most interesting topics in nuclear physics. 34Na has attracted additional attentions for an odd–odd nucleus with special structure. Here, we combine the complex momentum representation (CMR) and Green's function (GF) to establish the CMR-GF method for the exploration of exotic structure, such as halo, skin, the level inversion and so on, in 34Na. The available density distributions, the configuration occupations, and the root mean square radius for the orbit occupied by the last valence neutron suggest a p-wave single-neutron halo or skin structure in 34Na. [ABSTRACT FROM AUTHOR]

Starting from light to superheavy nuclei, we have calculated the effective surface properties such as the symmetry energy, neutron pressure, and symmetry energy curvature using the coherent density fluctuation model. The isotopic chains of O, Ca, Ni, Zr, Sn, Pb, and Z = 120 are considered in the present analysis, which cover nuclei over the whole nuclear chart. The matter density distributions of these nuclei along with the ground state bulk properties are calculated within the spherically symmetric effective field theory motivated relativistic mean field model by using the recently developed IOPB-I, FSUGarnet, and G3 parameter sets. The calculated results are compared with the predictions of the widely used NL3 parameter set and found to be in good agreement. We observe a few signatures of shell and/or sub-shell structure in the isotopic chains of nuclei. The present investigations are quite relevant for the synthesis of exotic nuclei with high isospin asymmetry, including superheavy nuclei, and also to constrain an equation of state of nuclear matter. [ABSTRACT FROM AUTHOR]

With the development of electron scattering experiments off exotic nuclei, many theoretical researches have been devoted to investigate the nuclear charge form factors recently. In this paper, we extend the studies of electron scattering by combing the deformed Hartree–Fock–Bogolyubov (HFB) model and the distorted wave Born approximation (DWBA) method. Comparing the theoretical with the experimental data, the validity of the deformed HFB model to describe the nuclear density distributions can be verified for both the spherical and deformed nuclei. By further investigating the of the isotopic chain, the effects of the nuclear deformation on the changing trends of of isotopes are provided. For even–even Xe isotopes, the nuclear deformation can influence the positions of the diffraction minima of. For odd-A Cs isotopes, the nuclear deformation can affect the values of diffraction minima of. The studies in this paper can offer useful guidances for the coming electron scattering experiments on unstable nuclei. [ABSTRACT FROM AUTHOR]

The ratio method has been developed to improve the study of one-neutron halo nuclei through reactions. By taking the ratio of angular distributions for two processes, viz. breakup and elastic scattering, this new observable is nearly independent of the reaction mechanism and hence much more sensitive to the projectile structure than the cross sections for each single process. We study the extension of the ratio method to proton-rich nuclei and also explore the optimum experimental conditions for measuring this new observable. We compare accurate dynamical calculations of reactions for proton-rich projectiles to the prediction of the ratio method. We use the dynamical eikonal approximation that provides good results for this kind of reaction at intermediate energy. Our tests for 8B, an archetypical one-proton halo nucleus, on Pb, Ni, and C targets at 44 MeV/nucleon show that, the ratio works less well than for neutron halos due to the non-negligible Coulomb interaction between the valence proton and the target. Nevertheless, thanks to its strong sensitivity to the single-particle structure of the projectile, the ratio method still provides pertinent information about nuclear structure on the proton-rich side of the valley of stability. To account for the lower quality of the method applied to charged systems, we suggest variations in its application from the original idea. Interestingly the method is not affected if energy ranges—or bins—are considered in the projectile continuum. This makes the ratio easier to measure experimentally by increasing the breakup cross section. We also extend our analysis to 17F, 25Al, and 27P, whose study is of interest to both nuclear astrophysics and nuclear structure. We show that, albeit less precise than for one-neutron halo nuclei, nuclear-structure information can be inferred from the ratio method applied to exotic proton-rich nuclei. For nuclei in which the valence proton is deeply bound and/or sits in an l ≥ 2 orbital, the method provides only estimates of nuclear-structure features, like the one-proton separation energy or the orbital angular momentum of the valence proton in the ground state. When the valence proton is loosely bound in an s or p orbital, viz. for proton halo nuclei, more detailed structure information can be obtained through this new reaction observable. [ABSTRACT FROM AUTHOR]

Within the dinuclear system model, the multinucleon transfer (MNT) reactions for producing exotic nuclei with Z = 17–20 close to the neutron-drip line are investigated. The inclusion of the temperature dependence of the pairing correction on the potential energy surface improves the description of experimental data reasonably well. With consideration of experimental conditions, the MNT process shows a huge advantage for producing the neutron-rich exotic nuclei 59,60Ca in comparison to the projectile fragmentation process. The MNT reaction 48Ca + 238U is proposed for producing 61,62Ca. [ABSTRACT FROM AUTHOR]

In order to describe the exotic nuclear structure in unstable odd-A or odd-odd nuclei, the deformed relativistic Hartree Bogoliubov theory in continuum is extended to incorporate the blocking effect due to the odd nucleon. For a microscopic and self-consistent description of pairing correlations, continuum, deformation, blocking effects, and the extended spatial density distribution in exotic nuclei, the deformed relativistic Hartree Bogoliubov equations are solved in a Woods-Saxon basis in which the radial wave functions have a proper asymptotic behavior at large r. The formalism and numerical details are provided. The code is checked by comparing the results with those of spherical relativistic continuum Hartree Bogoliubov theory in the nucleus 19O. The prolate deformed nucleus 15C is studied by examining the neutron levels and density distributions. [ABSTRACT FROM AUTHOR]

The properties of N = 7,8,9 isotones with Z = 4[?]8 are studied in the framework of the single-particle shell model. A tentative orbit-orbit coupling is introduced in the average nuclear potential. Calculations give a unified description of the structures of N=7,8,9 isotones. The neutron level inversion in N = 7 and N = 9 isotones is discussed. The ground-state level inversion in 11Be and 15C is reproduced. The inversion between 2s1/2 and 1d5/2 neutron levels in 14B and 13Be is predicted. The possible halo structures in N = 7 and N = 9 isotones are analysed. The numerical results confirm the one-neutron halo structures in 11Be(2s1/2), 11Be(1p1/2), 12B(2s1/2), 13C(2s1/2), 14B(2s1/2) and 15C(2s1/2). The study implies that the attempt of considering orbit-orbit interaction in the shell model may be a feasible way to explain the anomalous properties of exotic light nuclei. [ABSTRACT FROM AUTHOR]

Zlokazov and Utyonkov (2017 J. Phys. G: Nucl. Part. Phys.44 075107) question the validity of the methods and conclusions presented by Forsberg et al (2016 Nucl. Phys. A953 117). In this comment, we argue that the criticism is invalid. [ABSTRACT FROM AUTHOR]

Forsberg and Leino (2019 J. Phys. G: Nucl Part Phys46 018001) question the validity of criticism (2017 J. Phys. G: Nucl. Part. Phys.44 075107) of the method proposed by Forsberg et al (2016 Nucl. Phys. A 953 117). In this reply, we show that this method is based on unclear principles and its implementation leads to the results that contradict the conclusions following from mathematical statistics. [ABSTRACT FROM AUTHOR]

The behavior of α cluster preformation probability, in α decay, is a rich source of the structural information, such as the clustering, pairing, and shell evolution in heavy nuclei. Meanwhile, the experimental α decay data have been very recently compiled in the newest table NUBASE2016. Through a least square fit to the available experimental data of nuclear charge radii plus the neutron skin thickness, we obtain a new set of parameters for the two-parameter Fermi nucleon density distributions in target nuclei. Subsequently, we make use of these refreshed inputs, involved in the density-dependent cluster model, to extract α preformation factor () for a large range of medium α emitters with N < 126 from the newest data table. Besides checking the supposed smooth pattern of Pα in the open-shell region, the special attention has been paid to those exotic α-decaying nuclei around the Z = 50 and N = 82 shell closures. Moreover, the correlation between the α preformation factor and the microscopic correction of nuclear mass, corresponding to the effect of shell and pairing plus deformation, is in particular investigated, to pursue the valuable knowledge of the Pα pattern over the nuclide chart. The feature of α preformation factor along with the neutron–proton asymmetry is then detected and discussed to some extent. [ABSTRACT FROM AUTHOR]

Transfer reactions are a valuable tool to study the single-particle structure of nuclei. At radioactive beam facilities transfer reactions have to be performed in inverse kinematics. This creates a number of experimental challenges, but it also has some advantages over normal kinematics measurements. An overview of the experimental and theoretical methods for transfer reactions, especially with radioactive beams, is presented. Recent experimental results and highlights on shell evolution in exotic nuclei are discussed. [ABSTRACT FROM AUTHOR]

The advanced time-delayed (t) method has been used at ISOLDE since the relocation of the facility from the synchrocyclotron to the CERN proton synchrotron booster, a quarter of a century ago. The method was designed for precision measurements with low-intensity beams, achieving good efficiency and excellent time resolution with a compact setup. Over this time the technique has evolved to cope with the challenge of measuring lifetimes of complex level schemes of increasingly exotic nuclei populated in β decay. The ISOLDE facility provides unsurpassed opportunities to study many regions of the nuclide chart. The physics case encompasses topics of interest across the nuclide chart, including the evolution of shell structure around neutron shell and subshell closures such as N = 20, N = 40 and N = 50, shape coexistence, and octupole correlations in heavy nuclei. The recently commissioned ISOLDE decay station provides enhanced capabilities that will be fully exploited with the increased beam intensities available at the upcoming HIE-ISOLDE facility. [ABSTRACT FROM AUTHOR]

I will discuss the impact of the research on exotic nuclei carried out at ISOLDE and later on, following its impulse, in many laboratories worldwide, in our present knowledge of the nuclear dynamics. I will put particular emphasis on the occurrence of islands of inversion (IoI) at several magic numbers for the neutrons, far from stability. I will also discuss the appearance of new local shell closures in the calcium and silicon isotopic chains, and qualify their status as new doubly magic nuclei. [ABSTRACT FROM AUTHOR]

We report on studies of the beta-decays of 31Ar, Mg, and 16N performed at the ISOLDE decay station (IDS) at CERN. These studies illustrate how beta-decays measured with the IDS can be used to extract information of astrophysical interest, or to study the structure and decay mechanism of exotic nuclei. We discuss the specific implementation of the IDS designed for this type of studies including detector setups and data acquisition. [ABSTRACT FROM AUTHOR]

High-resolution γ-ray spectroscopy has been established at ISOLDE for nuclear-structure and nuclear-reaction studies with reaccelerated radioactive ion beams provided by the REX-ISOLDE facility. The MINIBALL spectrometer comprises 24 six-fold segmented, encapsulated high-purity germanium crystals. It was specially designed for highest γ-ray detection efficiency which is advantageous for low-intensity radioactive ion beams. The MINIBALL array has been used in numerous Coulomb-excitation and transfer-reaction experiments with exotic ion beams of energies up to 3 MeV A–1. The physics case covers a wide range of topics which are addressed with beams ranging from neutron-rich magnesium isotopes up to heavy radium isotopes. In the future the HIE-ISOLDE will allow the in-beam γ-ray spectroscopy program to proceed with higher secondary-beam intensity, higher beam energy and better beam quality. [ABSTRACT FROM AUTHOR]

The investigation of beta-delayed proton decay mode has become a powerful probe to study the proton-rich nuclei and their nuclear structure. To study exotic nuclei with extremely low purity produced by the Radioactive Ion Beam Line in Lanzhou, we perform an experiment of beta-delayed proton emission of 36,37Ca under a high-intensity continuous-beam mode. Ions are implanted into a double-sided silicon strip detector, where the subsequent decays are correlated to the preceding implantations in time sequence. The energy spectra of delayed protons from 36,37Caβ decay, half-lives and decay branching ratios are measured. The experimental results confirm the previous literature data and some improved results are obtained as well, demonstrating the feasibility of our detection approach and the reliability of our data analysis procedure. This allows for the development of more powerful detection arrays and further research on nuclei closer to proton-drip line on the basis of present work. [ABSTRACT FROM AUTHOR]

The open issues in the development of models for the breakup of exotic nuclei and the link with the extraction of structure information from experimental data are reviewed. The question of the improvement of the description of exotic nuclei within reaction models is approached in the perspective of previous analyses of the sensitivity of these models to that description. Future developments of reaction models are suggested, such as the inclusion of various channels within one model. The search for new reaction observables that can emphasize more details of exotic nuclear structure is also proposed. [ABSTRACT FROM AUTHOR]

Adjacent to the existing accelerator complex of the GSI Helmholtz Centre for Heavy Ion Research at Darmstadt, Germany, the Facility for Antiproton and Ion Research (FAIR) substantially expands research goals and technical possibilities. It will provide worldwide unique accelerator and experimental facilities allowing for a large variety of unprecedented fore-front research in hadron, nuclear and atomic physics as well as applied sciences which will be described briefly in this paper. The start version of FAIR, the so-called Modularized Start Version, will deliver first beams in 2017/2018. As an example the paper presents research efforts on strangeness at FAIR using heavy ion collisions, exotic nuclei from fragmentation and antiprotons to tackle various topics in this area. In particular hypernuclei and metastable exotic multi-hypernuclear objects will be investigated. [ABSTRACT FROM AUTHOR]

The anatomy of neck configuration in the fission decay of uranium and thorium isotopes is investigated in a microscopic study using relativistic mean field theory. The study includes 236U and 232Th in the valley of stability and exotic neutron rich isotopes 250U, 256U, 260U, 240Th, 250Th, 256Th likely to play an important role in the r-process nucleosynthesis in stellar evolution. Following the static fission path, the neck configurations are generated and their composition in terms of the number of neutrons and protons is obtained showing the progressive rise in the neutron component with the increase of mass number. Strong correlation between the neutron multiplicity in the fission decay and the number of neutrons in the neck is seen. The maximum neutron-proton ratio is about 5 for 260U and 256Th suggestive of the breakdown of the liquid-drop picture and inhibition of the fission decay in still heavier isotopes. Neck configuration as precursor of a new mode of fission decay like multi-fragmentation fission may also be inferred from this study. [ABSTRACT FROM AUTHOR]

The newly developed generalized density-dependent cluster model is employed to study the favored a transitions of exotic nuclei in both ground and isomeric states. We perform a systematic calculation for the ground and isomeric states of neutron-deficient isotopes ranging from Z = 67 to Z = 89. No adjustable parameter is introduced in our calculation. The theoretical a-decay half-lives are found to be in good agreement with the experimental data. This indicates that a unified description of a-decay half-lives for both ground and isomeric states is achieved by our model. [ABSTRACT FROM AUTHOR]

The recent observation of a positronium molecule (e[?]e+e[?]e+) by Cassidy and Mills (D B Cassidy and A P Mills 2007 Nature (London) 449 195) raises interest in other (fermionic) exotic systems. Similarly, the question arises whether larger bosonic systems can be formed. The variational method in a reformulated Hamiltonian formalism of quantum field theory is used to derive relativistic wave equations for a system consisting of three scalar particles and three scalar antiparticles (six-body problem) interacting via a massive or massless mediating scalar field (the scalar Yukawa model). Simple Fock-space variational trial states are used to derive relativistic six-body wave equations. The equations are shown to have the Schrodinger non-relativistic limits, with Coulombic interparticle potentials in the case of a massless mediating field and Yukawa interparticle potentials in the case of a massive mediating field. Approximate ground-state solutions of the six-body relativistic equations are obtained for various strengths of coupling, for both massive and massless mediating fields. [ABSTRACT FROM AUTHOR]

Though the phenomenon of quantum-mechanical interference has been known for many years, it still has many open questions. The present review discusses specifically how the interference of resonances may and does work. We collect data on the search for rare decay modes of well-known resonances that demonstrate a wide variety of possible different manifestations of interference. Some special kinds of resonance interference, not yet sufficiently studied and understood, are also briefly considered. The interference may give useful experimental procedures to search for new resonances with arbitrary quantum numbers, even with exotic ones, and to investigate their properties. [ABSTRACT FROM AUTHOR]

It is shown by explicit computations of binding energies that three-particle systems ppm, ddm and ttm interacting via the Debye-screened Coulomb interactions are bound beyond the limit for two-particle binding. [ABSTRACT FROM AUTHOR]

The technique of Penning trap mass spectrometry is briefly reviewed particularly in view of precision experiments on unstable nuclei, performed at different facilities worldwide. Selected examples of recent results emphasize the importance of high-precision mass measurements in various fields of physics. [ABSTRACT FROM AUTHOR]